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By Henry E. Colton

Very little information has been published concerning the Tennessee coal-field. The State never appropriated over $600 per annum for a geological survey, and that was discontinued about 1870. Yet even with that small sum Dr. J. M. Safford made a

Jan 1, 1886

(Members are urged to send in for this column any notes of interest concerning themselves or their fellow-members.) Members and guests who registered at Institute headquarters during the period Dec. 10, 1914, to Jan. 10, 1915: William E. Saunders, Philadelphia, Pa. H. J. Brown, Chester, Pa. F. H. Winsor, Jr., Salt Lake City, Utah. H. Mortimer-Lamb, Montreal, Canada. Cecil W. Pocock, Peru, S. A. B. W. Vallat, Detroit, Mich. Willet G. Miller, Toronto, Canada. W. D. B. Motter, Jr., Benson Mines, N. Y Adolphe E. Borie has resigned as Chairman of the Board of Directors of the Taylor-Wharton Iron & Steel Co., to devote his time to the American Road Machinery Co. and the Good Roads Machinery Co., as Chairman of the Board of Directors.

Jan 2, 1915

By Willard P. Ward

HAVING been engaged during the past year in the manufacture of ferro-manganese in a blast furnace, I have imagined that some further information on this subject might be of interest to that large number of members of the Institute who are engaged in the iron and steel industries. The great question of the economical production of good steel, ingot metal, or homogeneous iron (we scarcely know now what to call it) from good materials, and at reasonable prices, has, thanks to the intelligence and energy of a few American engineers, been successfully solved in this country. Nearly all first-class railroads, and many that would riot rank so high, have adopted the Bessemer rail. Martin boiler-plates are rapidly gaining ground, in competition with

Jan 1, 1877

By Willard P. Ward

Having been engaged during the past year in the manufacture of ferro-manganese in a blast furnace, I have imagined that some further information on this subject might be of interest to that large number of members of the Institute who are engaged in the iron and steel industries. The great question of the economical production of good steel, ingot metal, or homogeneous iron (we scarcely know now what to call it) from good materials, and at reasonable prices, has, thanks to the intelligence and energy of a few American engineers, been successfully solved in this country. Nearly all first-class railroads, and many that would not rank so high, have adopted the Bessemer rail. Martin boiler-plates are rapidly gaining ground, in competition with

By Arthur Notman

DESPITE the tremendous drop in the volume of domestic production of metals, their prices, and profits, the world as a whole has managed to produce and consume nearly as much as in 1937. Measured by production, 1937 was the record year for copper, lead, and zinc. The Copper Institute figures for 1938 (estimating December as equal to November) show that although apparent domestic consumption declined 309,422 tons, foreign consumption increased 133.035 tons. The total for 1938 was 1,971,790 tons compared with 2,148,177 tons for 1937. The domestic decline was 38.5 per cent, the foreign increase 9.9 per cent, and the total decline 8.2 per cent.

Jan 1, 1939

By C. H. Ma, J. S. Makris

This paper describes a modified X-ray diffraction microscope wzethod based on the general principles of Berg-Bawett's Method, Lang's Method, and Woosters1 Technique. This new method may be used for stationary or oscillatory photomacrographs, with both reflection and transmission techniques. In the stationary technique, a small point-source of a divergent X-ray beam of white radiation is used; in the oscillatory technique, a monochromatic divergent beam is employed. The chief advantages of the method described herein are that only approximate alignment of the Bragg angle -of-interest is needed during exposure, and that a large portion of a crystal-specimen surface can he irradiated. In recent years, the study of dislocations through X-ray diffraction microscope techniques has received considerable attention as concerns the per,fection of single crystals. Very promising results have appeared in the literature.'-' These techniques are very useful when the dislocation density of a crystal is near 105 per sq cm or lower. The principle of X-ray diffraction microscopy is based on the differential effect of X-ray primary extinction between the distorted parts and the perfect parts of a crystal. When an X-ray beam impinges on a set of planes of a crystal at the correct Bragg angle, diffraction of X-rays will occur with a 90-deg phase shift of the diffracted beam. This once-diffracted beam still forms the correct Bragg angle with the planes ahead of it, if the planes are not distorted. Thus, part of the strength of the once-diffracted beam is rediffracted and the beam continues to travel in the direction of the primary X-ray beam. This twice-diffracted beam not only takes away part of the strength of the once-diffracted beam, but also causes destructive interference with the primary beam because it now is exactly 180 deg out of phase with the primary beam. As the primary beam goes farther and farther into the crystal, its intensity is continuously weakened. Asa result, the ultimate X-ray diffraction power of a set of undistorted planes is largely extinguished. This phenomenon is called primary extinction.1,2'4 If the set of planes ahead of it is distorted, the once-diffracted beam will have less chance to be rediffracted, because it could not meet the exactly correct Bragg angle for rediffraction. If a part of the beam does rediffract, this twice-diffracted beam is not exactly 180 deg out of phase with the primary beam, and thus it causes less destructive interference. As a result, the registered X-ray diffraction power of the distorted part of a crystal appears stronger than that of the perfect part. Thus, point-by-point contrast of a diffraction image is theoretically possible from a crystal containing dislocations. Two most popular X-ray diffraction microscope techniques today are Berg-Barrett's Method and Lang's Method. Both of these techniques require a

Jan 1, 1964

By P. D. Merica

IN connection with other investigations on the properties and characteristics of chilled iron car wheels, the question as to the best range of annealing temperatures was raised. Chilled-iron wheels are cast with a chill against the tread and the inside of the flange, the remainder being in sand. The composition of the metal is so chosen that under these conditions the tread and inside of the flange will show white iron to a depth of from 5/8 to 7/8 in. (15 to 22 mm.), the remainder of the wheel becoming graphitized or gray. In order to relieve the stresses set up during cooling under such drastic conditions, the wheels are stripped from the mold, while still red hot, piled in a soaking pit, and allowed to cool very slowly from their temperature at stripping. Obviously the most suitable temperature for this annealing is the highest at which no formation of graphite occurs within the white tread and at which the wheels can be stripped from the molds. Inasmuch as no direct determinations have been made of the temperatures at which the' formation, of graphite takes place in white iron of compositions used in car wheels upon annealing, it was considered worth while to determine these temperatures as a means of establishing the maximum temperatures at which the annealing of the wheels may be carried out. In the course of this work, some incidental observations were made which are of interest in connection with the theory of graphitization in white iron. The literature on the subject of the formation of graphite both during cooling at casting and upon annealing is very extensive and can be best studied by reference to a comprehensive discussion of the subject by Hatfield. 1 Perhaps the most important contributions of previous investigation are the following: 1. Whether a given mass of molten iron becomes white, mottled, or gray upon casting, depends on its composition and its rate of cooling through the temperature range of solidification and immediately below.

Jan 7, 1919

By E. L. Davis

There have been many attempts to devise formulas for flowing efficiency and flow friction of oil-gas mixtures in oil-well flow tubes. Actually, however, flowing efficiency is rarely any real concern of the oil producer and flow-friction formulas contain so many unknown variables as to be of little, if any value. The production engineer is generally concerned with producing as much oil as possible with a minimum expense per barrel, and with the lowest possible net gas-oil ratio. These ends frequently are opposed to each other and the gas-oil ratio usually is sacrificed. In competitive operations, such as in town-lot fields, high current production is the sole interest. In conservative operation the greatest possible amount of oil obviously should be produced by natural flow unless the net formation gas-oil ratio can be improved by circulating gas. In practice this condition frequently exists. It would be a great advantage if the flowing condition of a well could be analyzed to determine the best possible producing status. Anticipating the death of a well so that gas-lift could be started immediately after the death, or preferably before, would save both production and expense. Frequently it happens that circulating gas fails to help a flowing well, or will not flow it after it has stopped flowing naturally. A knowledge of the laws governing flow would save considerable expense in testing such cases. A predetermination of probable pressures and amounts of circulating gas needed to flow wells and give best possible producing conditions would help in designing compressor installations. The optimum producing status of an oil well generally may be obtained by the conditions that subject the producing formations to the least possible back-pressure. This pressure is made up of the weight of the fluid column, frictional resistance to flow and the reaction from the acceleration of the fluid mass. A mathematical calculation of these components to arrive at a condition giving a minimum summation is impractical. Formulas would be complex and the results untrustworthy because it is impossible to assign proper values to the many variables involved.

Jan 1, 1931

By C. E. Beecher

The application of gas or air under pressure to obtain more oil from a sand which has been practically exhausted by ordinary production methods has been practiced to a limited extent for many years. Until recently such methods were confined to the Eastern fields, principally those of Ohio and West Virginia, where in many cases the production obtained after applying pressure for a few years was nearly equal to the total production prior to that time which had been obtained by the usual production methods. As early as 1917, J. 0. LewisL called attention to this method of increasing the recovery of oil and cited the phenomenal results obtained by H. E. Smith, I. L. Dunn and 0. C. Dunn, who pioneered the application of air or gas pressure recovery methods. With this information available it would appear that other oil-producing sections of the country have been extremely slow to realize the advantages of repressuring. However, after a few successful projects in the Mid-Continent area, the oil producers appreciated t' e value of this method for obtaining further and profitable production from their practically exhausted leases and are now making extensive use of it. In general, it has been the practice to apply pressure to the sands when production has declined to a small yield per well. The purpose of this paper is to discuss some of the advantages which may be expected from returning gas under pressure to the oil sands during the early stages of development, before the rock pressure has been dissipated and the gas exhausted, and to stimulate discussion of this subject on which comparatively little actual field data are available. The Function of Gas Gas associated with or dissolved in the oil is the source of energy causing movement of the oil to the well. When this energy is dissipated production ceases. The exception to this general statement is found in fields where hydrostatic water pressure may supply energy after the gas

Jan 1, 1929

Technology has no recognized rank in what is called polite literature; the subject-matter of engineering is not supposed to lend itself to artistic treatment; we are the hewers of wood and drawers of water to the high-priests of learning that live on the cold summit above our humbler dwellings. Therefore the hierophants smile at the notion of 'style'- “that curiously personal thing”--in technical writing. The "great art" of Pater, the "inevitable phrase" of Raleigh, the "note of distinction" that Arnold demanded are said to be beyond the scope, as they are supposed to be beside the need, of a writer on geology or engineering. This is a narrow view. Science, no less than belles lettres, calls for the best exercise of the human intelligence; the art of writing should be employed as skilfully and as earnestly in a description of the structure of the Sierra Nevada, or of the construction of a tunnel through the range, as in a rhapsody welcoming the rosy fingers of the dawn. The idea still lingers that fine writing does not befit technology, even though the masters of the Victorian period- Huxley, Tyndall, Ruskin-proved that science is worthy to be arrayed in the best robes that the looms of thought can weave. At the beginning of these lectures I quoted Barrie's remark touching the inability of the scientific man to express himself. That imputation has been passed to the technologist, whose utilitarian pursuits are supposed to make him too clumsy for the refinements of human speech. We may not have acquired the self-consciousness of those writers on Art whose "power of expression is so cultivated that their sensual caterwauling may be almost mistaken for the music of the spheres"; nor can we imitate the politicians, who have the ability to speak far beyond anything that they may have to say; but we too have a litera-

Jan 1, 1931

By Zay Jeffries

THIS paper will include a brief discussion of Prof. Howe's paper on The Supposed Reversal of Inheritance of Ferrite Grain Size from that of Austenite.1 The general subject of grain refining in steel and iron will also be treated. The conclusions reached are stated in the following hypotheses which are discussed more in detail below. 1. The ferrite grain size in pure iron, the ferrite and pearlite grain size in hypoeutectoid steel, the pearlite grain size in eutectoid steel and the cementite and pearlite grain size of hypereutectoid steel are not inherited from the grain size of the mother austenite. 2. The only structural feature that is generally inherited from the austenite of hypo- and hypereutectoid steels on cooling through their transformation ranges is the position of the excess ferrite or cementite at the austenite grain boundaries, sometimes causing complete and sometimes incomplete networks which outline the old austenite grain boundaries. Rapid cooling through the transformation range will cause the non-inheritance of this structural (network) feature. 3. The austenite grain boundaries themselves are nearly always effaced in all steels and also in pure iron during the Ar transformations. 4. The grain-size refining of steel and iron is brought about by the combined. effect of non-inheritance of the transformation products on either heating or cooling, i.e., the austenite transformation .products do not inherit their grain size from the austenite on cooling through the transformation range for does austenite inherit its grain size from the products which form austenite on heating. 5. In general, in both iron and carbon steel the larger the austenite ,grain size, the larger will be the grain size of the transformation products on cooling. This, of course, assumes all other conditions constant except the austenite grain size. An exception is found to this general rule in very pure iron such as electrolytic iron. 1n this instance small austenite grains may form very large ferrite grains on cooling through Ar3.

Jan 11, 1917

By A. Paul Bond

Two series of 17pct Cr iron-base alloys with small, controlled amounts of carbon and nitrogen were vacuum-melted in an effort to detertmine the meclz-uniswls of inter granulur corrosion in ferritic stain-less steels. An alloy containing 0.0095 pct N aid 0.002 pct C was very resistant to intergranular corrosion, even after sensitizing heat treatments at 1700" to 2100o F. However, alloys containing more than 0.022 pct Ni and more than 0.012 pct C were quite susceptible to intergranular corrosion after sensitizing heat treatments at temperatures higher than 1700°F. This corrosion was observed after the usual exposure tests and after potentiostatic polarization tests. Electronmicroscopic examination of the alloys susceptible to intergranular corvosion revealed a small grain boundary precipitate; this precipitate was absent in the alloys not susceptible to such corrosion. Thc electronmicrographs indicate that intergranu1ar corrosion of ferritic stainless steels is caused by the depletion of chromium in areas adjacent to precipi-tates of chromium carbide or chromium nitride. It also seems likely that the precipitates themselves are attacked at highly oxidizing potentials. Confirma-tion of the proposed mechanisms was obtained in tests on air-melted ferritic stainless steels containing titanium. The titanium additions greatly reduced susceptibility to intergranular corrosion at moderately oxidizing potentials but had no beneficial effect at highly oxidizing potentials. A major obstacle to the use of ferritic stainless steel has been their susceptibility to intergranular corrosion after welding or improper heat treatment. It appears that sensitization of ferritic stainless steel occurs under a wider range of conditions than for austenitic steels. In addition, a greater number of environments lead to damaging intergranular corrosion of sensitized ferritic stainless steels than to sensitized austenitic steels. The chromium depletion theory of intergranular corrosion is widely accepted for austenitic stainless steels'" although there: are some objections.3 On the other hand, several alternative mechanisms proposed for ferritic stainless steels include precipitation of easily corroded iron carbides at grain boundaries,' grain boundary precipitates that strain the metal lat-tice,5 and the formation of austenite at the grain bound-arie.6 The application of the chromium depletion theory to ferritic stainless steels has been discussed extensively by Baumel.7 The present investigation was undertaken to determine which of the proposed mechanisms can be sub- A PAUL BOND IS Research Group Leader, Climax Molybdenum Co of Michigan, Ann Arbor, Mich. stantiated with experimental data obtained on ferritic stainless steels. High-purity 17 pct Cr alloys containing small controlled additions of carbon or nitrogen were therefore prepared, and then examined electro-chemically and metallographically. EXPERIMENTAL PROCEDURES Materials. Two series of experimental alloys were prepared from electrolytic iron and low-carbon ferro-chromium using the split-heat technique. In this technique, the base composition is melted, and part of the melt is poured off to produce an ingot. To the balance of the melt, the required addition is made and the next ingot cast. This process is repeated until a series of the desired compositions is cast. By this procedure the impurity levels are essentially constant within each series. All the alloys in the carbon-containing series were melted and cast in vacuum. The base composition in the nitrogen series was melted and cast in vacuum; subsequent ingots in the series were melted with additions of high-nitrogen ferrochromium, and cast under argon at a pressure of 0.5 atmosphere. Two additional alloys were produced starting with normal purity materials. They were induction-melted while protected by an argon blanket and cast in air. Table I gives the composition of the alloys. The 2-in.-diam ingots produced were hot-forged and hot-rolled to a thickness of 0.3 in. and then cold-rolled to 0.15 in. All specimens were annealed at 1450°F for 1 hr. The indicated sensitizing heat treat-s s ments were performed on annealed material. All heat treatments were followed by a water quench. Specimen Preparation. For the 65 pct nitric acid test, 1 by 2 by 0.14-in. specimens were wet-surface ground to remove surface irregularities and polished through 3/0 dry metallographic paper. For the modified Strauss test, $ by 3 by 0.14-in. specinlens were similarly prepared. Immediately prior to testing, the Table I. Compositions of the Alloys Composition, pct Alloy Cr hio C N 270A 16.76 0.0021 0.0095 270B 16.74 0.0025 0.022 270C 16.87 0.0031 0.032 270D 16.71 0.0044 0.057 271A 16.81 0.012 0.0089 27 IB 16.76 0.018 0.0089 271C 16.69 0.027 0.0085 271D 16.81 0.061 0.0O71 4073' 18.45 1.97 0.034 0.045 4075† 18.5 2.0 0.03 0.03

Jan 1, 1970

By A. B. Stevens

IN the calculation of oil and gas reserves by volumetric methods, it is necessary to know the volume of the reservoir available for the storage of the oil or gas. To obtain this information, a number of methods for determining both total and effective porosity of reservoir rocks are used. For the determination of the total porosity, or the porosity that considers all of the pore spaces, connected and isolated, the Russell7,8,9 and the Melcher-Nutting1-6 methods are the best known and most- widely used in the petroleum industry. These methods have disadvantages in that they give the total porosity of the samples and in that the samples are reduced to grain size in the determination. In many sands there may be little or no difference between total and effective porosity but in other sands there may be considerable difference between the two. For the estimation of oil-and gas reserves the effective porosity of the reservoir rock always should be used. Of the methods that have been developed for the determination of the effective porosity of reservoir rocks, or the porosity that considers only those pore spaces that are connected, the best known are the so-called Boyle's law6,10-13, and the Washburn-Buntings.5,6,11 methods. The Wash-burn-Bunting method is probably the most widely used because it gives effective porosity, it is rapid, and the apparatus is inexpensive. This method employs a special porosimeter in which the core sample is placed in direct contact with mercury. This method has disadvantages in that, as a result of the high vacuum created in the pore spaces, mercury is drawn into the openings, making it impossible to use the sample for a check determination and also ruining the sample for any further test, such as permeability. The purpose of this paper is to describe an appa-ratus employing the same principle as the Washburn-Bunting method but so designed that the core sample does not come in contact with the mercury in the porosimeter.

Jan 1, 1939

This study of engineering education arose out of the action of a joint committee on engineering education, representing the principal engineering societies. The committee had gathered so much material that it decided the work could best be carried out by some one trained in applied' science, who would devote his entire attention to the study.. The Carnegie Foundation therefore asked Prof. Charles R. Mann, of the University of Chicago, to undertake the work. After making a thorough study Prof. Mann has made a most comprehensive report. In it he says: The engineering schools of the United States began their work upon a definite teaching plan and one that had at least pedagogic consistency. But during the past half century the course of study has been overlaid with many special studies intended to enable the student to deal with the constantly growing applications of science to the industries. As a result, the load upon the student has become so heavy that there is a feeling that the students fail to gain a satisfactory grounding in the fundamental sciences and do not fulfil the expectations of engineers in d manufacturers in dealing with the practical problems with which they are confronted on leaving school. At present 60 per cent. of those who enter the schools fail to graduate, still many of them persist in engineering and make a success of it. It is evident, therefore, that the present systems of admission are not satisfactory. If a group of schools will take up the careful study of their entrance systems and experiment with objective tests and records of the students' youthful interests and achievements, the percentage of elimination can be reduced to at least a fourth of its present size, with an enormous saving of time, energy, and money for both student and school. The number of required credit hours per week should be less than eighteen, preferably sixteen. The few experiments that have been made indicate that college students do their best work when not more than five subjects are studied at a given time.

Jan 1, 1919

By Joseph P. Hodgson

Since about 70 per cent. of the total cost of mining is due to underground work which is out of sight, it is essential that expenditures should be made here to the best advantage. A great many mistakes have been made which were expensive, but perhaps these have not even been detected by mine owners. In the future these may be minimized to some extent, especially if there is cooperative effort on the part of each employee. I have been interested in this subject for some years and have tried to deduce principles and methods. These have proved highly advantageous and may also be of help to others. Some corporations, like the United States Steel, and the Cleveland-Cliffs Iron Co., have done a great deal in this field by having stated meetings of their organizations, with the view to interchanging ideas among their men and educating them along the lines of concerted effort. Since no man knows all about the various branches of mining, it is advisable that frequent meetings of the operating department be held for the interchange of ideas and that all members of the organization have an opportunity to express themselves on the various subjects. It has often been found that in discussions between heads of departments, foremen and bosses, many valuable suggestions may be obtained which promote the best interests of the company. The method regarded as the most conducive to cooperative effort, and pursued by the organization, is to analyze and develop the different phases of various mining subjects at regular meetings. Nine Foremen's Dinners In the latter half of 1912, the Copper Queen Consolidated Mining Go. gave monthly dinners to the men in the operating departments. Those who attended were superintendents, foremen, shift bosses, engineers, geologists, and heads of all departments, making a total of about 75 men. After the dinner, lectures were given on subjects which pre-

Jan 1, 1917

By W. V. Green

Creep of tantalum was measured at temperatures from 0.6 to 0.89 of the absolute melting temperature. The creep curves include first, second, and third stages. Steady-state creep rate depends on the fourth power of stress. The activation energy for creep throughout this temperature range is approximately 114 kcal per mole, measured by the aT technique. Subgrain formation occurs as a result of creep strain, and pile-up dislocation arrays are observed in etch-pit patterns. BECAUSE of its high melting point-which is exceeded only by those of rhenium and tungsten—and its high room-temperature ductility compared to most of the other high-melting-point metals, tantalum will undoubtedly be utilized in an increasing number of high-temperature applications. Alloying studies directed toward increased high-temperature strength must use data on tantalum itself as a base line in order to evaluate the effectiveness of the alloying additions. However, to date, no systematic study of creep of tantalum at temperatures above one-half of its melting point has been reported in the literature. Conway, Salyards, McCullough, and Flagella1 have measured linear creep rate of tantalum sheet as a function of stress, but at only one temperature, 2600°C. This paper describes a relatively thorough study of the high-temperature creep of tantalum. METHOD Material Tested. The commercially supplied, l/2-innch-diameter tantalum rod used for this work was electron-beam-melted, cold-forged, rolled, swaged, cleaned chemically, and vacuum-annealed for 1 hr at 1000°C, all by its manufacturer. The vendor's analysis included 60 to 170 ppm C, 3.4 to 4.2 ppm H, 60 to 80 ppm 0, 15 ppm N, and a hardness ranging from 66 to 81 Bhn and averaging 76 Bhn. Creep eimens Used. Two creep-tested specimens are shown in Fig. 1. The 1/4 in.-diameter gage section was 3/4 to 1 in. long, and terminated either at shoulders 5 mils high or at 20-mil-diameter tantalum wires spot-welded to the circumference of the gage section. Both kinds of shoulders served equally well as fiducial marks for optical strain measurements. The spot welding did not alter the creep behavior in any detectable way; the 5-mil- high sharp shoulders did not result in any detectable localized effect on the strain. Before testing, each tensile bar was first mechanically polished -id then electrochemically polished according to the method referred to by Forgeng2 as the "Thompson Ramo Woolridge" method, which was suitable for tantalum after small adjustments of technique were made. Two tensile bars tested at low stresses had 1/8-in.-diameter gage sections and utilized only the weight of the bottom grip for the applied load. Although these diameters were smaller than were desired for other reasons, applied loads were known with high precision in the tests in which they were used. Testing Procedure. Two different constant-load creep-testing machines were employed, one of which has been described by Smith, Olson, and Brown.3 In both, the tensile bar is held vertically on the axis of a cylindrical tungsten tube or screen heater by threaded tungsten grips. The tensile bars and associated grips are heated by radiation from the incandescent heaters, which are heated by their own electrical resistance. Both testing machines use pins to hold the bottom grips in place. The load is applied to a tensile bar through hanging weights, a constant force-multiplication lever, a pull rod sealed to the chamber lid, and a top grip threaded to the pull rod at one end and to the tensile bar at the other. In one machine, the vacuum seal is a bellows with a low spring constant; in the other, the seal involves a rotating "0 ring". With the latter, rotation is converted to translation with a crank shaft, so that elongation of the tensile bar is accommodated with no change of tensile load. The incandescent tensile bar is viewed by an external optical system through slots in the radiation shields and heater, and an enlarged image is projected on a ground-glass screen. Gage-length measurements are made on this image with cathetometers on traveling microscopes. With regard to creep-test results, the two machines were identical. Thorium oxide coatings were applied to the threaded ends of the tensile bars, to prevent diffusion welding of the tensile bars to the grips during testing. Specimen temperatures were measured with an L. & N. optical pyrometer which had been calibrated against a standard carbon arc, and were corrected fir window absorption by calculation from the measured spectral transmittance of the quartz observation windows. Longitudinal temperature gradients in the tensile-bar gage length and temperature drifts during testing were detectable but small, and were estimated to be 10°C or less. Accuracy of temperature measurement was confirmed by comparing the temperature measured on the surface of a special

Jan 1, 1965

By Owen Rice

CHANGES in coke hardness affect the working of the blast furnace, for soft coke is an obstacle to proper furnace operation. Soft coke is due to a low hydrogen-oxygen ratio in the coal charged; increasing this ratio increases the hardness of the coke. The best means of determining the hardness of coke is the combined tumbler and ball-mill. Soft coke is a great hindrance to proper blast-furnace operation and changes in coke hardness affect the working of the furnace. The best method of determining the hardness of coke is by using a combination tumbler-ball-mill. Soft coke is due to a low hydrogen-oxygen ratio in the coal charged. An increase of this ratio improves the hardness of the resulting coke. WHAT IS GOOD COKE? It is not always appreciated that the correct answer may be such a reliable forecast to the physical condition of the blast furnace, and incidentally its entire operation, that among the ordinary variations in other raw materials and also in operating conditions, it assumes a position of primary significance. Inasmuch as coke forms two-thirds of the total bulk of material charged, this assertion will not seem exaggerated, and in the subsequent discussion its applicability will be presented. Coke is the ideal blast-furnace fuel because it is strong and hard enough to resist the crushing and grinding effects of the furnace burden, and its porosity allows the ready passage of gas upward through the charge, and rapid combustion before the tuyeres. Coke deprived of its strength and with a cell structure physically frail and chemically susceptible to solution by carbon dioxide, has its chief asset eliminated. When the melting zones are approached the fluid cinder trickling toward the hearth will envelope the small pieces of coke and form a sticky mass that will retard the free passage of gas. Blast pressure will then rise, driving

Jan 1, 1921

By A. N. Mitinsky

Discussion of the paper of A. N. MITINSKY, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 104, August, 1915, pp. 1697 to 1705. LAWFORD H. FRY, Burnham, Pa. (communication to the Secretary*). -The author assumes that the proportional limit and the elastic limit are coincident or very nearly so, and then further assumes that the stress corresponding to these two points is the least stress which if repeated will cause failure. The point is extremely interesting and it is to be regretted that the author did not quote experimental data to show the relation between the limit of repeated stress and the other properties of the material. The author's suggestion that a steel of poor quality may have a normal value for the yield point and tensile strength (see Fig. 2) and an abnormally low elastic limit, and that this will correspond to a low resistance to repeated stress, may account for a number of failures of axles in which the tensile tests show normal physical properties. If so and if a determination of the proportional limit would have eliminated the material before it was put into service, this determination will merit most earnest attention. It appears, however, that considerable further research is necessary before any definite conclusion as to the quality of a steel can be drawn from its proportional limit. Mr. Mitinsky's paper is extremely interesting and if it stimulates thought and work along the lines indicated, it may prove of considerable practical benefit. H. V. WILLE, Philadelphia, Pa.-The paper discusses the difference between the proportional limit, or elastic limit, and the yield point, and refers to the fact that much harm results from confusion of the terms yield point and elastic limit. Similar confusion has arisen in this country; the American-Society for Testing Materials does not even consider the elastic limit and proportional limit to be identical and recently adopted the following definitions:

Jan 12, 1915

By W. F. Rochow, W. C. Burke

Numerous designs of linings and accessories, including dams, lifters, and heat exchangers, contribute greatly to kiln efficiencies. Greater conductivity is achieved with basic brick than with fireclay and high-alumina refractories, depending largely upon the use of steel plates in radial joints between adjacent brick to increase heat transfer through the lining. Refractory lifters expose all portions of the load to radiant or convective heat and raise some portions to higher temperatures by cascading the load down through the path of the hot gases. AMONG the many factors involved in rotary kiln efficiency, advantageous use of refractories is of major importance. So far as kiln lining alone is concerned durability is most significant, as shutdowns for repairs are costly in fuel consumption and production losses. Aside from selection of refractories best suited to the widely varying conditions under which rotary kilns are operated, lining design and accessory constructions within the kiln are highly important. The refractory most economical for any combination of operating conditions can be selected from a wide range of alumina-silica and basic refractories, including insulating, castable, and plastic fire bricks. In several cases silica brick can be used to advantage. Alumina contents of alumina-silica refractories range from 35 to 90 pct in increments of 5 to 10 pct. In general, bricks of relatively low alumina content are best for abrasion resistance, an important property for the brick used in chain sections of cement kilns or in feed end sections of limestone kilns. High-duty fireclay bricks of approximately 40 pct alumina and 55 pct silica are used to line the intermediate zones. Super-duty fireclay brick at slightly higher cost is warranted in operation of kilns with high intermediate zone temperatures and severe spalling conditions. Alumina-silica refractories with an alumina content of 50 pct and higher, termed high-alumina brick, are available in commercial classes of 50, 60, 70, 80, 85, and 90 pct alumina content. These refractories are generally used as high temperature zone linings or placed adjacent to the basic brick-lined sections when the treatment they are required to withstand is excessively severe. Use of basic refractories is confined mainly to zones of maximum temperature and most severe chemical action. Basic refractories ordinarily employed for high temperature zone linings of many rotary kilns comprise the classes shown in Table I. Each class is peculiarly well suited to various particular combinations of working conditions. The approximate chemical analyses of these classes also illustrate differences in compositions with respect to the major components.

Jan 1, 1956

By E. H. Fahmy, L. C. Uren

During recent years, oil producers have observed with interest the practical success which has attended the application of water as a medium for displacement of oil from its reservoir sands in the Bradford field of northern Pennsylvania and southern New York. Here, according to various authorities, additional recoveries of frorn 2,000 to 12,000 bhl. of oil per acre have heen secured by this method, after ordinary flowing and pumping. rnethods of production had practically reached the lower limit of economic operation. Notwithstanding the success which has attended the practical use of the flooding process in the Bradford field, oil producers in other regions are skeptical of its value when applied under physical conditions differing markedly from those which characterizc the Bradford field. Its usc would probably he construed as illegal in most of the oil-producing states. This general relnctance on the part of oil producers in other regions to accept the flooding process is due in large part to lack of infor-n~ation regarding the factors that influence its operation and efficiency. With the purpose of clarifying to some extent the issues involved, and of determining when the flooding proccess may or may not beeffee-tivcly ernployed, the writers have conducted a serics of laboratory exper-imentments under carefully controlled conditions, designed to indicate, the influence of various physical, chemical arid lithologic factors. These experments have not been conducted under conditions identical with those which exist at depths far below the earth's surface, so that direct quantitative comparisons with field results are not justified, hut it is believed that the experimental results at least warrant qualitative inter-pretations that may he applied to field conditions. The methods employed in the conduct of these experiments are briefly explained, and the results, together with the conclusions based thereon, arc presented. FactoRs Influencing Displacement of Oil froM SaNdS by WAteR- flooding Before presenting the experimental data, it, will he desirable to con-sider the manner in which the residual oil is retained within the oil sand

Jan 1, 1928